I as of yet have not been able to cost justify purchasing a scan tool, but at the price they are at the present it is not much of a stretch to say a purchase would not be in order. I would want something that can read my 2007 car along with my 95 and 94 even though both of those I can diddle with the key and count codes with a flashing check engine light. They are limited in scope even if they are available and have proven useful.
It should also have the capacity to deal with anything up to this year that I might foreseeable by in the future over the next couple of years.
But Harbor Freight sells a perfectly functional Digital Voltmeter for $2.00 on sale and I keep them all over the place because they are cheap and useful.
It costs more to keep good batteries in them then it did to buy them in the first place and they will adequately make most measurements that can be done on your car.

 

Well checked the voltage at the battery tonight with the car idling it was 14.9 so that means the alt. is putting out. It really acts like a clogged converter but when i put my hand over the tailpipe it has a good amount of pressure which makes be believe thats not a problem plus i dont know if that would cause major codes if it was clogged!

 

I have owned 2 cars that ended up plagued with clogged converters. One was a car purchased new in 1978 and as converter technology was relatively new at that point in time and many manufactures used the flat converter developed by GM there were not many types nor applications around. Smog certification being what they were some model cars depending on what engine and carburetor they had will still being made that did not automatically require one. That car suffered from excessive overheating aggravated by the length of the trip, very poopy performance and blown exhaust pipe gaskets. It took the dealer well over a year to figure out what the problem was and then it was a factory recall that solved it.
The 2nd car was actually my 94 Saturn. They symptom was running hot on very long trips and a noise when starting that sounded like throwing pea gravel on a metal heat shield that can be seen around the catalytic converter. In this case there was no noticeable change in performance. Running hot was only observable by looking at the heat gauge and as can be seen here on the forums, the accuracy of the heat gauge was also a factor of the sensor located in the cylinder head thus some question of how accurate the gauge was always was open for judgement.
That essentially was discovered a few years back when I went through it solving a number of problems accumulated through time and had the Catalytic Converter cut out and replaced with a universal high flow catalytic converter that is popular here locally as a generic cat replacement item. I have one on another car too. That solved the rattly noise and no longer did it appear to run hot on a long trip running hard. Neither car exhibited any problem doing grocery store runs. You had to be out on the open road trying to make time before the running hot indications showed up.
As to the codes? Neither car ever showed a check engine light in normal operation unless it was also very hot so the codes were never checked.
Dunno, times and computers change.
The 78 had a pretty dumb computer in it and the 94 compared to today's computer engine and body management systems was not that much smarter.

 

Well made some progress i think tonight got another scan tool that did read the lw correctly i erased all the codes and rechecked it without starting it P1516 code stayed then i started it and two other showed up P1780 and U2107 the scanner stated the most common fix was the PCM then thottle body then mass airflow sensor. I did tap on the MAF the other day to see if any change in idle happened and one time the idle did stumble but only one so that may have been a fluke.
Where Is the Pcm on this car bolted to the back valve cover? and is it also the ECM or they different modules?

 

In my own mind I equate the two as being the same thing. I look up the definition and PCM becomes powertrain control module and I think it dates back to early computer controlled vehicles. Those from the early 80's were generally simpler and were usually throttle body types. They were both simpler and required no changes in intake manifold technology and were more or less an electronic carburetor for all practical purposes and it seems to me that the engine control computer was tagged by that name which is where I remember it from.
Of course it common that different manufacturers come up with some cutesy name that their advertising department can use to differentiate their car from some one else's.
The first throttle body car I owned was a 1980 Dodge Aries available with a Mitsubishi 2.6 or Chryslers 2.2. Mine was the 2.2. Ignition timing was controlled by the PCM which had a vacuum advance canister hooked to a potentiometer inside the PCM that controlled the engine. Of course that was an analog to digital conversion, another technical function in the jargon applied to the acronym PCM
I really don't know whether the Acronym ECM is a universal way of defining the computer that controls the engine or not. Or just a GM name applied to it.
Most of my fuel injection experience is with a Chrysler application over the years and a Camero and my Saturn. My other cars are mostly AMC and they went to Electronic Feed Back Carburetors some where in the late 70's and other than the fuel injection used on the Jeep 4.0L engine that replaced the GM 2.8 V6 in the Cherokee which was a French design and the replaced by a MOPAR unit used nothing but Electronic Feedback Carter BBD carburetors and an extremely simple computer which I believe was also referred to as a PCM.
All that is in part a reason why I stay away from using acronyms. For the most part people have no clue what they mean with out looking them up. They have a tendency to change meaning between automotive manufacturers and I really do not know what a universal term is and I guess I really don't care. I try to define a piece functionally if I do not know the name and let it be at that.
I am not sure that my Saturn uses a Mass Air Flow sensor. I have not had a problem that required me to figure it out. My 87 Olds though did and as it was a Company Car that required it to be maintained under fleet guide lines it went to oil change facilities that gave receipts. And every time the supposed mechanic removed the air filter to show me that it needed a new one whether it did or not they damaged the Mass Air Flow sensor and back to the dealer it went to get a replacement. It usually took awhile for it to take place though so it was never instantaneous and the only thing I remember it doing was to turn on the check engine light. I do not remember a drive-ability problem. I can see where a mass air flow sensor can cause problems if it is going to though. That is good technology and very adaptable to modifications. As it measures air flow usage and with in certain parameters can compensate for engine modifications.
A Speed Density design does not use a mass air flow sensor. It is assumed that at a given rpm there will be a given amount of air used and the calculations are then based on RPM vs various sensor positions. A simpler system but as long as modifications are kept with in a window, works with them. Other wise you crutch the design by changing to injectors with a higher flow rate or insert an offset into something like a MMAP sensor so it's signal to the ECM or PCM reflects different operating conditions thus changing how things are controlled.
I don't have documentation that covers your car as to where the electronic parts are located. Sorry can not help as to where it is.

 

As to code definitions, those I apparently do have. I can copy those out on hard copy. To pass them on requires me to re-scan them as a jpg and attach to an e-mail or as a picture on a forum post or send them out as part of a snail mail deal.
If that is needed lemme know and I will try.

 

Went to the junk yard today and found two ecm's with different numbers from what i have so i bought them to try out i figured they would not work but wanted to try something. plugged them in and found both had stored codes cleared them and tried to start the car with no luck but no codes reset plugged the old ecm back in and it has the codes in it even after clearing so that kinda tells me that is the problem. I guess finding a used one with the same numbers is like finding a needle in a haystack so what are the options are reman. units preprogrammed any good? If i buy a new gm unit can the program it without the car being there?

 

I don't know so can't answer that. I have never been backed that far into a corner. I am just some what aware that pretty much many of the newer Saturn parts are getting harder to get locally. I have heard some pretty Bazaar stories on availability.

 

Many models require programming to the unit to the vehicle VIN & mileage and certain applications require additional information before the car will start and run. I believe thats the case with all SATURNS.............................

 

I heard and read a few guys that had good results with reman'd cardone units i may give that a shot and also call the dealer and get some insight.